Your 22 year old female patient is c/o severe burning with urination, fever of 101, and aching all over. She takes oral contraceptives. She reports one new partner within the last month. Palpation of the inguinal nodes reveals bilateral lymphadenopathy. There are more than 10 shallow ulcers along each side of the vulva. She is very tender at the introitus. Urine has some WBCs but no RBCs or bacteria. Which disorder of the vulva is most likely?

Correct Answer: A

Rationale: The correct answer is A: Genital herpes. The patient's symptoms of severe burning with urination, fever, aching, new sexual partner, bilateral lymphadenopathy, multiple shallow ulcers along the vulva, tenderness at the introitus, and absence of RBCs or bacteria in urine are all consistent with genital herpes. Genital herpes is caused by the herpes simplex virus (HSV) and presents with painful vesicular lesions in the genital area. The presence of ulcers and lymphadenopathy points towards an infectious etiology. Condylomata acuminata (choice B) presents as genital warts caused by HPV, which typically do not cause ulcers. Syphilitic chancre (choice C) presents as a painless ulcer with a firm base, not multiple ulcers. Epidermoid cyst (choice D) presents as a benign skin lesion, not with the symptoms described.

Correct Answer: B

Rationale: The correct answer is B because in nephrogenic diabetes insipidus, the kidney tubules are unable to respond to antidiuretic hormone (ADH). This results in the inability to concentrate urine, leading to excessive dilute urine output. Lines A and D in the figure represent a high urine output (polyuria) and low urine osmolality, which are characteristic of nephrogenic diabetes insipidus. Choice A (A and C) is incorrect because line C does not show low urine osmolality. Choice C (B and C) is incorrect because line B does not show high urine output. Choice D (B and D) is incorrect because line D does not show low urine osmolality.

Correct Answer: A

Rationale: Step 1: Newborn infants have limited hepatic capacity to store and synthesize glycogen and glucose. Step 2: This limited capacity results in the plasma glucose concentration not being maintained in a normal range for more than a few hours after feeding. Step 3: Feeding every few hours ensures a constant supply of glucose to maintain plasma glucose levels. Step 4: Thus, it is important to feed newborn infants every few hours to prevent hypoglycemia. Summary: A: Correct - Maintaining plasma glucose levels due to limited hepatic capacity. B: Incorrect - Protein concentration is not the primary concern for feeding frequency. C: Incorrect - Keeping food in the stomach constantly does not improve gastrointestinal function. D: Incorrect - Hypoproteinemic edema is not the primary reason for feeding frequency.

Correct Answer: D

Rationale: The correct answer is D: Abnormally high levels of testosterone in the maternal blood. This can cause virilization of the female fetus, leading to the development of male external genitalia. Testosterone exposure during fetal development can result in the formation of a penis and scrotum without testes in a genetic female (XX). Rationale: 1. Testosterone is responsible for the development of male external genitalia. 2. XX chromosomes indicate a genetic female. 3. Lack of testes indicates incomplete masculinization. 4. High levels of testosterone can override the default female development pattern. Other choices are incorrect because: A: Human chorionic gonadotropin does not directly affect fetal genital development. B: Estrogen is not responsible for male genital development. C: Luteinizing hormone does not directly influence the development of external genitalia in the fetus.

Correct Answer: D

Rationale: Step 1: The trophoblast cells of the blastocyst invade the endometrial lining during implantation. Step 2: The trophoblast cells secrete enzymes to digest the nutrient-rich endometrial cells. Step 3: The digested nutrients are absorbed by the trophoblast cells. Step 4: These nutrients are then utilized by the blastocyst for its growth and development. Step 5: This process ensures that the blastocyst receives the necessary nutrition for the first week after implantation. Summary: A: Incorrect. Endometrial secretions are no longer the source of nutrition after implantation. B: Incorrect. While the blastocyst may contain some stored nutrients, they are not sufficient for the first week post-implantation. C: Incorrect. The placenta is not fully functional until later in pregnancy, so it does not provide nutrition in the first week.